CAUSES.-In a large majority of cases it is due to an abuse of alcohol, tobacco, or more frequently of both, and hence is found almost exclusively in males, and in them not generally until middle life. When due to alcohol it is more apt to be found in those who seldom or never drink to intoxication, but who indulge in frequent drinks daily. Noyes (loc. cit.) found, out of 204 cases, that 132 were due to these causes. The remaining cases in the table cited by Noyes were due to diabetes, lead, bisulphide of carbon, syphilis, multiple sclerosis, cold, menstrual disturbances, pregnancy,, loss of blood from abortion, anomaly of heart, periostitis orbitae, and in 32 cases the cause was unknown. Many other drugs, such as iodoform, the coal tar products, arsenic, quinine, salicylic acid, etc., are also causes of toxic amblyopia. That tobacco alone can cause a retro-bulbar neuritis has been denied by some, but sufficient cases have been reported to make it certain in our opinion that it may.
PROGNOSIS.- In the early stage, before atrophy of the optic nerve has occurred, the prognosis may be considered favorable, as more or less complete recovery may be expected if the patients will give up their use of tobacco and alcohol. In some cases the sight will return to normal, even though triangular atrophy of the disc remains.
TREATMENT.- When due to alcohol or tobacco, total abstinence from all spirituous liquors and tobacco must be strictly enforced; after which our attention should be turned to those remedies which will restore the whole system to its natural tone. The hypodermic injection of strychnine has proven of value in some cases that would nor yield to other remedies.
Nux vomica has been, and probably always will be, the most important and most commonly indicated remedy in this trouble. The results following its use are often marvellous. There are no marked eye symptom in this disease, and therefore nothing to guide us to this drug with the exception of the cause.
Arsenic seems especially adapted to loss of vision dependent upon the use of tobacco, and has proven clinically to be of the first value in retro-bulbar neuritis.
Terebinth.-Amblyopia potatorum, with dull aching pain in the back and dark-colored urine.
Atrophy of the Optic Nerve.-This disease may occur in any part of the nerve from the eye to it origin, and, when present, may extend in either direction. Atrophy may be sub- divided into non-inflammatory and inflammatory type.
Non-inflammatory (simple, primary or genuine) atrophy is that form where the wasting away of the nerve substance has not been preceded by visible signs of inflammation, although Loring believed that all cases, if seen early enough and examined with sufficient care, would have shown evidences of inflammation.
Inflammatory atrophy is that form occurring as the result of a neuritis or a retinitis. This variety is also sometimes spoken of as a neuritic or retinitic atrophy.
PATHOLOGY.-Atrophy consists of changes in all the nerve elements; there is degeneration of the nerve-fibres, and interspersed between the fibres are found fat globules, granular cells and amyloid corpuscles; there is an increase of the connective tissue; the walls of the blood-vessels become thickened and their calibre reduced; the nerve-fibres are reduced; to an indifferent structure; the whole nerve becomes smaller and appears to be changed into a cord of connective tissue. The medullary substance is first affected. In gray atrophy, in addition to these changes, the nerve assumes a gray, translucent and jelly-like appearance and a gelatinous substance may be found around the vessels.
SYMPTOMS.–The loss of central vision varies all the way from a slight depreciation to blindness, and if both eyes are affected, it is apt to be more advanced in one than the other. The contraction of the field of vision is always a well- marked defect, but is not indicative of the cause of the atrophy; it usually commences as concentric, peripheric narrowing. The limitation may begin in any direction and as a rule advances concentrically, but is usually well advanced before central vision begins to decline; hence, if there is any paleness of the nerve or suspected atrophy, the field of vision should be carefully examined. Occasionally we find an irregular contraction of the field, which will cause a peripheral scotoma corresponding to the defect and it may occur either with or without concentric narrowing. Central scotoma which points to lesion of the macular fibres is rarely in the stages, yet it may occur. Hemianopsia, or complete loss half of the visual field, may also be found. In this the same of each eye is usually affected, although it has been in simple atrophy affecting the inner half of each retina, and in this respect simulating the limitation due to cerebral disease.
There is always a defect in the color vision in all kinds of atrophy. Green is usually first affected and is confounded with the gray or yellow color’s; following the loss of the green will be that of the red, blue, yellow and white in the order named, although exceptionally red may be lost first. Contraction of the color-field is usually much greater than that for form. Dilatation of the pupil is often present in complete atrophy, and frequently will show no contraction when light is thrown into the eye, but may do so in the act of convergence. When atrophy is present in but one eye, and the pupil makes no contraction from the stimulus of light thrown into that eye, if the light be thrown into the unaffected eye instant contraction will take place in the diseased eye.
The ophthalmoscopic appearances in atrophy of the optic nerve are always distinctive and characteristic. (See Chromo- Lithograph Fig.5, Plate III.) The first change is the reduction in the amount of the circulation, which first affects the capillaries at the outer part of the disc because they are less numerous in this location. Diminution in the amount of the vascularity in the temporal part of the disc results in a slight paleness, in contrast with which the vessels from the nasal side appear more distinct, and on account of this it may be mistaken for a congestion. The paleness then commences on the nasal side and finally extends over the entire surface of the disc. The diminution or disappearance of the capillaries often constitutes all the changes that occur in the vessels, as in some cases the larger vessels will remain normal for years (in inflammatory atrophy vessels are also contracted).
The alteration in the color of the optic disc admits of considerable variations, from a slight gray to a white hue, and sometimes it assumes a greenish or bluish cast. Its outlines are distinct and clear cut, especially so in advanced cases. Much care and consideration is always required to distinguish a slight pathological paleness of the nerve from that which is normal or physiological, whiteness of the disc may vary decidedly in health. The of the optic disc in atrophy is due to the want of capillary and to the over-development connective tissue. Owing to shrinking or wasting away of the substance of the nerve in atrophy, the size of the disc appears, and is in reality, smaller than normal. The surface of the disc is flattened or concave, and the extent of the concavity will vary, depending somewhat upon the degree of the normal physiological cup; while the depth of the excavation depends upon the degree of nerve-fibre degeneration that has taken place. At the bottom of the excavation in atrophy the lamina cribrosa is usually distinctly seen and has a mottled-gray appearance.
Inflammatory atrophy differs from the non-inflammatory, in that the papilla shows connective tissue changes due to organization of the exudate. The neuritic atrophy gives a grayish-white color to the disc, margins ill-defined, veins and tortuous. Later the disc becomes a bluish-white, smaller in size, clear cut. the vessels contracted, and we do not see the lamina cribrosa as in the inflammatory type. In retinitic atrophy the disc is of grayish-red color and clouded, margins indistinct and vessels greatly diminished in calibre.
The surrounding fundus, in atrophy following papillitis or retinitis, will frequently show spots of degeneration and masses of pigment here and there, indicating previous inflammatory changes and haemorrhages. In simple gray or white atrophy these spots are not seen.
COURSE.-In optic nerve atrophy the course depends somewhat upon the cause, but is always slow, lasting for months and in many cases taking years to run its course to complete blindness. Non-inflammatory atrophy generally occurs in middle life and men seem to more subject to it than women. The atrophy of children is as a rule neuritic.
CAUSES.- Gray degeneration occurs in sclerosis and paralysis of the insane, but generally as a result of some disease of the spinal cord, especially tabes dorsalis by far the most frequent cause of non-inflammatory atrophy. This atrophy usually comes on in the early stage of tabes and with the Argyll-Robertson pupil and the absence of patellar reflex, which are also often early symptoms, affords valuable aid in the diagnosis of this disease. As to the general causes, Noyes (loc. cit.) gives the following table of the causes of atrophy in 183 cases by Uhthoff:
Professor of Ophthalmology in the College of the New York Ophthalmic Hospital; Surgeon to the New York Ophthalmic Hospital. Visiting Oculist to the Laura Franklin Free Hospital for Children; Ex-President American Homoeopathic Ophthalmological, Otological and Laryngological Society. First Vice-President American Institute of Homoeopathy : President Homoeopathic Medical Society of the State of New York ; Editor Homoeopathic Eye. Ear and Throat Journal : Associate Editor. Department of Ophthalmology, North American Journal of Homoeopathy, etc.